Enzymatic synthesis of pyridine heterocyclic compounds and their thermal stability.

An efficient method was discovered for catalyzing the esterification under air using Novozym 435 to obtain pyridine esters. The following conditions were found to be optimal: 60 mg of Novozyme 435, 5.0 mL of n-hexane, a molar ratio of 2:1 for nicotinic acids (0.4 mmol) to alcohols (0.2 mmol), 0.25 g of molecular sieve 3A, a revolution speed of 150 rpm, a reaction temperature of 50 °C, and reaction time of 48 h. Under nine cycles of Novozym 435, the 80 % yield was consistently obtained. Optimum conditions were used to synthesize 23 pyridine esters, including five novel compounds. Among them, gas chromatography-mass spectrometry-olfactometry (GC-MS-O) showed phenethyl nicotinate (3g), (E)-hex-4-en-1-yl nicotinate (3m), and octyl nicotinate (3n) possessed strong aromas. Thermogravimetric analysis (TG) revealed that the compounds 3g, 3m and 3n exhibited stability at the specified temperature. This finding provides theoretical support for adding pyridine esters fragrance to high-temperature processed food.

Rational design of Near-Infrared fluorescent probe for monitoring HNO in plants.

Nitroxyl (HNO), a reactive nitrogen species (RNS), is essential for plant growth. However, the action of HNO in plants has been difficult to understand due to the lack of highly sensitive and real-time in-situ monitoring tools. Herein, we presented a near-infrared fluorescent probe, DCI-HNO, based on dicyanoisophorone fluorophore, for real-time mapping HNO in plants. The introduction of a phosphine moiety as a specific HNO recognition unit can inhibit the intramolecular charge transfer (ICT) of probe DCI-HNO. However, in the presence of HNO, the ICT process occurred, leading to the emission at 665 nm. Probe DCI-HNO exhibited high sensitivity (97 nM), rapid response time (8 min), large Stokes shift (135 nm) for detection of HNO in plants. The novel developed probe has successfully imaged endogenous HNO produced during NO/H2S cross-talk in plant tissues. Additionally, the up-regulated in HNO levels during tobacco aging and in response to stress has been confirmed. Therefore, probe DCI-HNO has provided a reliable method for monitoring the NO/H2S cross-talk and revealing the role of HNO in plants.

Naked-eye detection of plant viral disease using polymerase chain reaction amplification and DNAzyme.

Plant viral diseases can seriously affect the yield and quality of crops. In this work, a convenient and highly sensitive biosensor for the visual detection of plant viral disease is proposed by the PCR-induced generation of DNAzyme. In the absence of nucleic acid for a target plant virus, the primers prohibited the production of G-quadruplex by forming a hairpin structure. However, PCR amplification occurred and generated a number of specific PCR products with free G-quadruplex sequences at both ends in the presence of the target cDNA. A catalytically active G-quadruplex DNAzyme was formed with the help of K+ and hemin, resulting in the formation of colored products visible to the naked eye and a strong absorbance by the addition of ABTS2- and H2O2. The absorbance and the logarithm of target cDNA concentrations showed a good linear relationship in the range of 10 fM-1.0 nM, with a linear regression equation of A = 0.1402 lg c + 0.3761 (c: fM) and a detection limit of 0.19 fM. This method was successfully applied to the analysis of emerging tobacco mosaic virus (TMV) infections in tobacco leaf samples collected in the field due to its flexibility and convenience, indicating a potential application for the early detection of plant viral disease.

Moisturizing and aroma-enhancing effects of low molecular weight fenugreek polysaccharides in cigarettes.

Polysaccharides possess excellent moisturizing effects due to their abundance of hydrophilic groups and film-forming properties. Additionally, they can produce a refreshing aroma during the pyrolysis process. However, there is scarce research on their application in the tobacco field. Herein, we investigated the effects of low molecular weight fenugreek polysaccharide (FP) obtained through ethanol fractionation and DEAE-52 cellulose column chromatography on moisture retention and aroma enhancement in tobacco. The moisture retention test revealed that the addition of FP increased the moisture retention index (MRI) of tobacco by 11.72 %-16.69 %, indicating that the hydrophilic nature of polysaccharides facilitated the migration of free water in tobacco to bound water, resulting in reduced water activity. Moreover, the contact angle between polysaccharide and tobacco was <90°, enabling better infiltration into tobacco and slowing down tobacco shrinkage caused by water loss. Among all the components, EFP-20 and EFP-40 demonstrated superior performance. Furthermore, FP exhibited excellent thermal stability below 200 °C and can decomposed to produce aromatic substances at high temperatures. It also demonstrated the ability to adsorb ethyl heptanoate and thermally decompose to produce a substantial amount of heptanoic acid. Consequently, the incorporation of FP in tobacco demonstrated favorable effects on both moisturization and aroma enhancement.

Hydrogel-potassium humate composite alleviates cadmium toxicity of tobacco by regulating Cd bioavailability.

Cadmium (Cd) removal from soil to reduce Cd accumulation in plants is essential for agroecology, food safety, and human health. Cd enters plants from soil and affects plant growth and development. Hydrogels can easily combine with Cd, thereby altering its bioavailability in soil. However, few studies have evaluated the effects of hydrogel on the complex phytotoxicity caused by Cd uptake in plants and the microbial community structure. Herein, a new poly (acrylic acid)-grafted starch and potassium humate composite (S/K/AA) hydrogel was added to soil to evaluate its impact on tobacco growth and the soil microenvironment. The results indicate that the addition of S/K/AA hydrogel can significantly improve the biomass, chlorophyll (Chl) content, and photosynthetic capacity of tobacco plants during Cd stress conditions, and decrease Cd concentration, probably by affecting Cd absorption through the expression of Cd absorption transporters (e.g., NRAMP5, NRAMP3, and IRT1). Moreover, the application of S/K/AA hydrogel not only reduced the accumulation of reactive oxygen species (ROS), but also reduced the antioxidant activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT), suggesting that S/K/AA hydrogel alleviates Cd toxicity via a non-antioxidant pathway. Notably, we further analyzed the effectiveness of the hydrogel on microbial communities in Cd-contaminated soil and found that it increased the Cd-tolerant microbial community (Arthrobacter, Massilia, Streptomyces), enhancing the remediation ability of Cd-contaminated soil and helping tobacco plants to alleviate Cd toxicity. Overall, our study provides primary insights into how S/K/AA hydrogel affects Cd bioavailability and alleviates Cd toxicity in plants.

Fluorescent probes for lighting up ferroptotic cell death: A review.

Ferroptosis is a newly discovered form of regulated cellular demise, characterized by the accumulation of intracellular oxidative stress that is dependent on iron. Ferroptosis plays a crucial role not only in the development and treatment of tumors but also in the pathogenesis of neurodegenerative diseases and illnesses related to ischemia-reperfusion injury. This mode of cell death possesses distinctive properties that differentiate it from other forms of cell death, including unique morphological changes at both the cellular and subcellular levels, as well as molecular features that can be detected using specific methods. The use of fluorescent probes has become an invaluable means of detecting ferroptosis, owing to their high sensitivity, real-time in situ monitoring capabilities, and minimal damage to biological samples. This review comprehensively elucidates the physiological mechanisms underlying ferroptosis, while also detailing the development of fluorescent probes capable of detecting ferroptosis-related active species across various cellular compartments, including organelles, the nucleus, and the cell membrane. Additionally, the review explores how the dynamic changes and location of active species from different cellular compartments can influence the ignition and execution of ferroptotic cell death. Finally, we discuss the future challenges and opportunities for imaging ferroptosis. We believe that this review will not only aid in the elucidation of ferroptosis's physiological mechanisms but also facilitate the identification of novel treatment targets and means of accurately diagnosing and treating ferroptosis-related diseases.

Nickel-Catalyzed Amidation of Aryl Alkynyl Acids with Tetraalkylthiuram Disulfides: A Facile Synthesis of Aryl Alkynyl Amides.

Nickel-catalyzed amidation of aryl alkynyl acids using tetraalkylthiuram disulfides as the amine source is described, affording a series of aryl alkynyl amides in good to excellent yields under mild conditions. This general methodology provides an alternative pathway for the synthesis of useful aryl alkynyl amides in an operationally simple manner, which shows its practical synthetic value in organic synthesis. The mechanism of this transformation was explored through control experiments and DFT calculations.

Impact of inactivated COVID-19 vaccines on lung injury in B.1.617.2 (Delta) variant-infected patients.

BACKGROUND: Chest computerized tomography (CT) scan is an important strategy that quantifies the severity of COVID-19 pneumonia. To what extent inactivated COVID-19 vaccines could impact the COVID-19 pneumonia on chest CT is not clear. METHODS: This study recruited 357 SARS-COV-2 B.1.617.2 (Delta) variant-infected patients admitted to the Second Hospital of Nanjing from July to August 2021. An artificial intelligence-assisted CT imaging system was used to quantify the severity of COVID-19 pneumonia. We compared the volume of infection (VOI), percentage of infection (POI) and chest CT scores among patients with different vaccination statuses. RESULTS: Of the 357 Delta variant-infected patients included for analysis, 105 were unvaccinated, 72 were partially vaccinated and 180 were fully vaccinated. Fully vaccination had the least lung injuries when quantified by VOI (median VOI of 222.4 cm3, 126.6 cm3 and 39.9 cm3 in unvaccinated, partially vaccinated and fully vaccinated, respectively; p < 0.001), POI (median POI of 7.60%, 3.55% and 1.20% in unvaccinated, partially vaccinated and fully vaccinated, respectively; p < 0.001) and chest CT scores (median CT score of 8.00, 6.00 and 4.00 in unvaccinated, partially vaccinated and fully vaccinated, respectively; p < 0.001). After adjustment for age, sex, comorbidity, time from illness onset to hospitalization and viral load, fully vaccination but not partial vaccination was significantly associated with less lung injuries quantified by VOI {adjust coefficient[95%CI] for "full vaccination": - 106.10(- 167.30,44.89); p < 0.001}, POI {adjust coefficient[95%CI] for "full vaccination": - 3.88(- 5.96, - 1.79); p = 0.001} and chest CT scores {adjust coefficient[95%CI] for "full vaccination": - 1.81(- 2.72, - 0.91); p < 0.001}. The extent of reduction of pulmonary injuries was more profound in fully vaccinated patients with older age, having underlying diseases, and being female sex, as demonstrated by relatively larger absolute values of adjusted coefficients. Finally, even within the non-severe COVID-19 population, fully vaccinated patients were found to have less lung injuries. CONCLUSION: Fully vaccination but not partially vaccination could significantly protect lung injury manifested on chest CT. Our study provides additional evidence to encourage a full course of vaccination.

Moisture Property and Thermal Behavior of Two Novel Synthesized Polyol Pyrrole Esters in Tobacco.

To overcome the shortcomings of high relative humidity and harmful oxidation products from traditional humectants, excellent humectants and flavor precursors were reported herein. Glucosamine hydrochloride was used as the starting material for the cyclization, oxidation, and alkylation processes that produced pyrrole acid. Then, esterification occurred with polyol catalyzed by EDC and DMAP to give the target compounds 2-(2,3-dihydroxypropyl) 4-methyl 5-methyl-1-propyl-1H-pyrrole-2,4-dicarboxylate (Gpe) and (2-hydroxypropyl) 4-methyl 5-methyl-1-propyl-1H-pyrrole-2,4-dicarboxylate (Ppe). Nuclear magnetic resonance (1H NMR, 13C NMR), infrared spectroscopy (IR), and high-resolution mass recorded spectrometry (HRMS) were used to confirm the two novel polyol pyrrole ester compounds. When Gpe and Ppe were added to the tobacco shred, low-field nuclear magnetic resonance (LF-NMR) imaging was applied to assess the hygroscopicity and moisturizing capacity. Furthermore, thermogravimetry (TG) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) techniques were applied to study their thermal behaviors. These results showed that the target compounds (Gpe and Ppe) are good humectants with thermal properties of high-temperature stability and flavor release.

Microbial community and metabolic function analysis of cigar tobacco leaves during fermentation.

Cigar tobacco leaves (CTLs) contain abundant bacteria and fungi that are vital to leaf quality during fermentation. In this study, artificial fermentation was used for the fermentation of CTLs since it was more controllable and efficient than natural aging. The bacterial and fungal community structure and composition in unfermented and fermented CTLs were determined to understand the effects of microbes on the characteristics of CTLs during artificial fermentation. The relationship between the chemical contents and alterations in the microbial composition was evaluated, and the functions of bacteria and fungi in fermented CTLs were predicted to determine the possible metabolic pathways. After artificial fermentation, the bacterial and fungal community structure significantly changed in CTLs. The total nitrate and nicotine contents were most readily affected by the bacterial and fungal communities, respectively. FAPROTAX software predictions of the bacterial community revealed increases in functions related to compound transformation after fermentation. FUNGuild predictions of the fungal community revealed an increase in the content of saprotrophic fungi after fermentation. These data provide information regarding the artificial fermentation mechanism of CTLs and will inform safety and quality improvements.

Remediation of lead and cadmium from simulated groundwater in loess region in northwestern China using permeable reactive barrier filled with environmentally friendly mixed adsorbents.

Permeable reactive barrier (PRB) is potentially effective for groundwater remediation, especially using environmentally friendly mixed fillers in representative areas, such as semi-arid loess region in northwestern China. The mixed materials, including corn straw (agricultural wastes), fly ash (industrial wastes), zeolite synthesized from fly ash (reutilized products), and iron-manganese nodule derived from loess (materials with regional characteristics) in northwestern China, were chosen as PRB media to reduce the contents of lead and cadmium in simulated groundwater. A series of lab-scale column experiments were investigated, and the response surface methodology (RSM) was used to optimize the working process; Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM) were applied to further reveal the reaction mechanism. It shows that the purification efficiencies are more acceptable when the concentrations of lead and cadmium are approximately 7 and 0.7 mg/L, respectively, at 25 °C in weakly acidic solution, and functional groups of -OH and C=C play an important role for contaminants removal. The mixed adsorbents used are effective to remove lead and cadmium in groundwater. This is the first report on the removal of lead and cadmium from groundwater in loess region in northwestern China using PRB filled with environmentally friendly mixed adsorbents.

Effects of histone deacetylase inhibitor sodium butyrate on heroin seeking behavior in the nucleus accumbens in rats.

Histone acetylation and other modifications of the chromatin are important regulators of gene expression and may contribute to drug-induced behaviors and neuroplasticity. Inhibition of histone deacetylases (HDAC) activity results in the change of some drug-induced behaviors，however, relatively little is known about the effects of HDAC inhibitors on heroin-seeking behavior. In the present study, male rats were trained to self-administer heroin under a FR1 schedule for consecutive 14 days, followed by 14 daily 2h extinction session in the operant chamber. After training, the heroin priming (250µg/kg) was introduced for the reinstatement of heroin-seeking behavior. Pretreatment with sodium butyrate (NaB) (200 or 400mg/kg, i.p.), an inhibitor of HDAC, failed to affect heroin self-administration. Additionally，systemic administration of NaB (400mg/kg, i.p.)increased significantly the reinstatement of heroin-seeking induced by heroin priming when NaB administered 12h, but not 6h before the reinstatement test. The same effect was observed after the intracerebroventricular injection of NaB (5µL, 100µg/µL). Moreover, the levels of histone H3 acetylation at lysine 18（H3K18）and H4 acetylation at lysine 5 or lysine 8（H4K5 or H4K8）in the accumbens nucleus core and shell were remarkably increased during the reinstatement and were further strengthened after intracerebroventricular injection of NaB. These results demonstrated that activation of histone acetylation may be involved in the heroin-seeking behavior, and identifying these epigenetic changes will be critical in proposing a novel pharmacological strategy for treating heroin addiction.

[Pyrolysates of novel latent fragrant compound 3,6-dimethyl-2,5-pyrazinedicarboxylic acid menthol ester].

In order to develop a new tobacco flavor released at high-temperature, the novel latent fragrant compound 3,6-dimethyl-2,5-pyrazinedicarboxylic acid menthol ester (DPAME) was synthesized by esterification using 2,3,5,6-tetramethylpyrazine and menthol as raw materials. In air atmosphere, the pyrolysis behavior of DPAME was investigated using an on-line pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) method at three temperature levels of 300, 600 and 900 degrees C, separately. The pyrolysis products were directly introduced into GC-MS and were qualitatively and semi-quantitatively analyzed. The results showed that a variety of aroma compounds of aldehydes, 3-p-menthene and menthol were released and identified at 300 degrees C. While at 600 degrees C and 900 degrees C, flavor alkene class, the alkyl pyrazines, menthol and 3-p-menthene were generated. And the types and relative amounts of pyrazines were significantly increased, at these two temperatures. Combined the analytical results of DPAME pyrolysates and the results of sensory evaluation of the cigarette, the possible pyrolysis mechanism was preliminarily speculated. The Py-GC-MS technique for the study of the pyrolysis products of DPAME was convenient and rapid. The investigation provided a reliable theoretical foundation for the perfume reinforcement technology in tobacco products, contributing to the development of cigarette products with better aroma and taste. This method is an accurate and quick way to study the pyrolysis products of latent fragrant substance.

Chaperones are the target in aloe-emodin-induced human lung nonsmall carcinoma H460 cell apoptosis.

Our previous study has demonstrated that aloe-emodin induced a significant change in the expression of apoptosis-related proteins in H460 cells. However, the molecular mechanisms underlying the biological effects of aloe-emodin still remain unknown. The present study applied 2D electrophoresis (pH range 4-7) to the proteins involved in aloe-emodin (40 muM)-induced H460 cell apoptosis. Eleven proteins were found to markedly change. These altered proteins were identified as ATP synthase, vimentin, HSP60, HSP70 and protein disulfide isomerase. Aloe-emodin caused a time-dependent decrease in intracellular ATP levels, which might be related to direct inhibition of ATP synthase. We also observed that the activity of mitochondria was injured by aloe-emodin. These data clearly demonstrated that mitochondria may play a critical role in aloe-emodin-induced H460 cell death. Many reports emphasize that chaperones have a complex role in apoptosis. The present study suggested that the increasing protein expression of HSP60, HSP70, 150 kDa oxygen-regulated protein and protein disulfide isomerase is involved in aloe-emodin-induced H460 cell apoptosis. HSP70, 150 kDa oxygen-regulated protein and protein disulfide isomerase are endoplasmic reticulum chaperone. Therefore, we hypothesized that the increasing endoplasmic reticulum stress serves to promote H460 cell apoptosis after treatment with aloe-emodin. We also demonstrated aloe-emodin-induced H460 cell death through caspase-3 apoptotic pathway, but not apoptosis-inducing factor apoptotic pathway.

Microinjection of M(5) muscarinic receptor antisense oligonucleotide into VTA inhibits FosB expression in the NAc and the hippocampus of heroin sensitized rats.

OBJECTIVE: To investigate the effect of M(5) muscarinic receptor subtype on the locomotor sensitization induced by heroin priming, and it's effect on the FosB expression in the nucleus accumbens (NAc) and the hippocampus in the heroin sensitized rats. METHODS: Locomotor activity was measured every 10 min for 1 h after subcutaneous injection of heroin. FosB expression was assayed by immunohistochemistry, and the antisense oligonucleotides (AS-ONs) targeting M(5) muscarinic receptor was transferred with the lipofectin. RESULTS: Microinjection of AS-ONs targeting M(5) muscarinic receptor in the ventral tegmental area (VTA) blocked the expression of behavioral sensitization induced by heroin priming in rats. Meanwhile, the expression of FosB-positive neurons in either the NAc or the dentate gyrus (DG) of the hippocampus increased in heroin-induced locomotor sensitized rats. The enhancement of FosB-positive neurons in the NAc or DG could be inhibited by microinjection of M(5) muscarinic receptor AS-ONs into the VTA before the heroin-induced locomotor sensitization was performed. In contrast, microinjection of M(5) muscarinic receptor sense oligonucleotide (S-ONs) into the VTA did not block the expression of behavioral sensitization or the expression of FosB in the NAc or DG in the heroin sensitized rats. CONCLUSION: Blocking M(5) muscarinic receptor in the VTA inhibits the expression of heroin-induced locomotor sensitization, which is associated with the regulation of FosB expression in the NAc and hippocampus neurons. M(5) muscarinic receptor may be a useful pharmacological target for the treatment of heroin addiction.

Up-regulation of matrix metalloproteinase family gene involvement in ursolic acid-induced human lung non-small carcinoma cell apoptosis.

Ursolic acid is a triterpenoid reported to inhibit the invasion of cancer cells. In this study, there was a significant increase in the gene expression of matrix metalloproteinase (MMP)-1, -2 -3, -9 and -10 in H460 cells after treatment with 10 microM ursolic acid for 24 h. Under these experimental conditions, it was found that ursolic acid induced H460 cell apoptosis. These results indicated that matrix metalloproteinase family members are involved not only in invasion, but also in apoptosis of cancer cells. It has been suggested that ursolic acid acts via a glucocorticoid receptor in the regulation of MMP. Our study also demonstrated that the localization of glucocorticoid receptor in the cytosol might be an important factor of MMP up-regulation during ursolic acid-induced H460 cell apoptosis. Ursolic acid induced a typical apoptosis on H460 cells, which was characterized by the activation of caspase-3, nuclear morphological changes and DNA fragmentation.

[Intrathecal injection of muscarinic receptors or GDNF antisense oligonucleotides inhibits the increase of c-Fos expression in locus coeruleus of morphine-withdrawal rats].

The antisense approach and immunohistochemistry were used to study the effects of different muscarinic receptor (M) subtypes and glial cell derived neurotrophic factor (GDNF) on the scores of morphine-withdrawal syndrome and the expression of c-Fos in locus coeruleus (LC). Intrathecal injection of M2 receptor antisense oligonucleotides (M2AS-oligo) or GDNF antisense oligonucleotides (GDNFAS-oligo) decreased the scores of morphine withdrawal syndrome. The expression of c-Fos positive neurons in the LC increased in morphine-dependent rats and increased to a greater extent after the injection of naloxone (4mg/kg, ip) in morphine dependent rats. Intrathecal injection of M2AS-oligo or GDNFAS-oligo inhibited the increase of c-Fos expression in LC during morphine withdrawal, but there was no effect in case of M1AS-oligo. The results suggest that M2 receptor of spinal cord mediates the neural activation of LC during morphine withdrawal. And the interaction between neurons and glial cells may be involved in the ascending activation process.

Baicalein induced cell cycle arrest and apoptosis in human lung squamous carcinoma CH27 cells.

Baicalein, a flavonoid compound, is one of the active constituents of the root of Scutellariae Radix. Baicalein inhibited the growth of human lung squamous carcinoma CH27 cells in a dose-dependent manner. Cell cycle analysis revealed an increase in the S-phase cell population following 24-h exposure to 50 microM baicalein. During the S-phase arrest, analysis of cell cycle regulatory molecules demonstrated that baicalein decreased the levels of cdk 4, cyclin B1 and cyclin D1. Furthermore, baicalein (50 microM) significantly induced cell apoptosis after 3 days of treatment. Baicalein induced apoptosis, as confirmed by condensed nuclei and DNA fragmentation, in CH27 cells. Baicalein-induced apoptosis was also accompanied by a decrease in Bcl-2 and caspase-3 proform levels. These results suggest that baicalein inhibits the proliferation of CH27 cells via S-phase arrest and apoptosis.